Holding rail arrangement

ABSTRACT

A holding rail arrangement for a holding device on a coordinate table of a punching press, comprising holding rails fixed on a transverse carriage of the coordinate table, the holding rail being arranged on a plate carried on the transverse carriage, the plate being pressed by yielding holding means against the transverse carriage.

United States Patent [191 [111 3,802,687 Bredow 1 Apr. 9, 197 4 HOLDINGRAIL ARRANGEMENT 3,5911 12 7/1971 DeGeorge et a1 83/409 x 1 Inventor:Walter Bredow, Ziegelmasch 16a, 33??32? $393532122;::113:3::iiiiiiijiijiiiiiijijiii 23283 322 Alfeld, Germany i A 21972 [22] Flled pr Primary Examiner-Harold D. Whitehead [21] Appl. No.2248,3 5 Assistant Examiner-Harold P. Smith, Jr. Attorney, Agent, orFirm-Holman & Stern [30] Foreign Application Priority Data June 2, l97lGermany 2l27249 [57] ABSTRACT [52] US. Cl 269/56, 83/409, 83/62,

269/285, 269/321 ME A holding rail arrangement for a holding device on a[5 lI-Itoordinate table of a punching press omprising hold- Field ofSearch 56, rails fixed on a transverse carriage f'the oordi- 321 621,63, nate table, the holding rail being arranged on a plate 409; 51/240A, 240 R carried on the transverse carriage, the plate being pressed byyielding holding means against the trans- [56] References Cited versecarriage.

UNITED STATES PATENTS 2,339,926 1/1944 Hays 269/97 X 5 Claims, 5 DrawingFigures iMENTED APR 9 I974 SHED 1 OF 4 $.95 iii ||Itmh|1w W l tL fi UWJfi'U] fi v n U A UH U a T1 w? Q Rm HOLDING RAIL ARRANGEMENT BACKGROUNDOF THE INVENTION The invention relates to a holding rail arrangement,and more particularly to such an arrangement on which the holdingdevices of a coordinate table are attached. Previouslyproposed holdingrails of this type are normally attached by screw means to thetransverse carriage of the coordinate table and pinned in position. Thistype of attachment has the disadvantage that more particularly in thecase of numerically controlled coordinate tables any collision betweenthe transverse carriage or the holding device attached to it with aturret punching press cooperating with the coordinate table leads tounavoidable damage to the coordinate table. On the other hand, it is notpossible to avoid completely collisions between the table and themachine, either owing toincorrect programming or owing to die breakage.Holding devices have been previously proposed which are in a position togive way when the holding devices or the workpieces which are held bythem, abut against the machine. Such holding devices with a securitydevice, however, offer the disadvantage that they are comparativelycomplicated and expensive. Furthermore, there is the disadvantage thatfor each workpiece at least two holding devices are required. In thecase of large workpieces generally more than two holding devices must beemployed.

One aim of the present invention is to provide a holding railarrangement which prevents any collision damage while being simple inconstruction.

' The present invention consists in a holding rail arrangement for aholding device on a coordinate table of a punching press, comprisingholding rails fixed on a transverse carriage of the coordinate table,the holding rail being arranged on a plate carried on the transversecarriage, the plate being pressed by yielding holding means against thetransverse carriage. With this arrangement it is possible to ensure thatthe holding rail is so connected with the transverse carriage that fornormal operation the holding rail is fixedly coupled with the transversecarriage .in such a manner that it cannot make any movements in relationto the transverse carriage but, if a collision should occur between theholding device or the workpiece and the machine, it can move out of theway or yield so that an electric switch can be simultaneously operatedwhich puts the coordinate table out of operation.

In the case of one embodiment of the invention the yielding holdingmeans comprise a pin fixed in the transverse carriage, a disc with aconicalseat fitting against the conical dished portion of the plate, ahelical spring carried on this disc, a pressing disc transmitting thepressing force of the spring and at least one setting nut, which arescrewed on the upper end of the pin. It has been found that such anarrangement operates without any trouble at all.

In order to keep the mass of the moving parts of a coordinate table assmall as possible, the transverse carriage is frequently made of lightmetal, while on the other hand the holding rail must in every case bemade of steel. Owing to the different coefficients of thermal expansionof these two materials difficulties frequently arise when the holdingrail is fixed by means of screws and pinned to the coordinate table. Thepresent invention makes it possible to avoid such difficulties.

In order to makepossible relative longitudinal movements between theplate mentioned which is made of steel and the transverse carriage whichis made of light metal,'the resilientholding means are arranged on thecontinuous rails with an oblique: seating surface. In ordertobring abouta further improvement the attachment points of theholding rail on thetransverse car- 'riage are constructed differently. One point is, forexample, arranged as afixed :point, while the second is so constructedthat it allows for different longitudinal expansion of the holding rail.

In the case of a long length of the holding railor of the associatedtransverse carriage three holding points are provided for. In this casethe fixed point can be in the middle and a holding point can be arrangedto the left and to the right of it respectively, the latter holdingpoints allowing for expansion in the longitudinal direction. t

The accompanying drawing shows an embodiment of the invention by way ofexample.

FIG. 1 shows a plan view of a holding rail with two attachment points.

FIG. 2 is a view of the holding rail with partial sections in accordancewith the line of section A-B of FIG.

FIG. 3 shows a section through the fixed holding point in accordancewith the line of section C-D of FIG. 1.

FIG. 4 is a section through the fixing point allowing movement inaccordance with the section E-F of FIG.

FIG. 5 shows a section through the holding rail with the arrangement ofan electric switch in accordance with the section G-H of FIG. 1.

In the case of the embodiment of the invention shown in FIGS. 1, 2 and 3a holding rail is shown with two plates 71 and 72 fixed on it. FIG. 3shows a section through a fixing point. In theplate 71 a conical dishedportion or recess 73 is provided. The connection with the transversecarriage 81 is brought about via the pin 75, nuts 82, the disc 76, andthe conical disc 74 with an interposed helical spring 78. In order tokeep as small as possible the friction between the conical disc 74 andthe pin 75 a conical bush 77 is provided. The attachment of the bolt 75with the transverse carriage 81 is ensured by means of the disc 79 andscrews 80. If the holding rail 70 is so strongly loaded by a blow or bya tension force that the force perpendicular to the bolt 75 is greaterthan the pressing force of the spring 78, the conical disc 74 slides outof the conical recess 73 and the holding rail 70, including the plate 71attached to it, can recede before the excesive loading. In FIG. 1 thelightening slots 92 which are milled out to reduce the weight of theholding rail are also shown. FIG. 3 additionally shows these lighteningslots 92 in section and the recess 91, in which an attachment screw 93is arranged.

In FIG. 4 of the embodiment shown one attachment or fixation point isshown, which allows a longitudinal movement of the holding rail inrelation to the transverse carriage 81, for example owing to changes intemperature. In the plate 72 there is no conical dished recess as inFIG. 3 but two rails 83, whose adjacent edges 83' are made oblique so asto make an angle of 45 to each other with the result that a :relativelongitudinal movement between the holding rail 70 which is made ofsteel, and the transverse carriage 81, which is made of light metal, ispossible.

FIG. 5 shows the details of the arrangement of the electric switch 85.When the holding rail 70 has been moved out of the position intended forit, operation of the coordinate table must be stopped at once asotherwise the punching operations would not be carried out by the turretpunching press at the correct positions since the workpiece is no longerin the exact required position. In order to be able to switch off thecoordinate table electric switches 85 are provided at each holding orgripping point. The plungers 85' of the electric switches are arrangedto be acted upon by pressing screw 86. At that instant in whichdisplacement of the holding rail 70 occurs, the pressing screw 86releases the respective plunger 85 of the electric switch 85 so that theswitch 85 responds and thus the switching off of the drive of thecoordinate table can be started. The electric switch 85 is attached tothe switch holder 87. The switch holder 87 is attached to the transversecarriage 81 by means of the screw 88. Reference numeral 89 denotes aconical pin and reference numeral 90 screws, with which the electricswitch 85 is fixed on the switch holder 87. In the top left-hand part ofthe drawing the lightening slots 92 are indicated. In the recess 91 theattachment screw 93 is again accommodated.

The invention relates to holding devices on coordinate tables forpunching presses, more particularly turret punching presses, in whichthe holding rails are fixed to the transverse carriage of the coordinatetables. The invention is, however, capable of being put into practice inother machine tools on which controlled, more particularly numericallycontrolled coordinate tables are provided, in the case of which the sameaim may occur as is the case with the present application. Thedescription thus relates to a particular embodiment of the invention asapplied to numerically controlled coordinate tables of turret punchingpresses.

verse carriage at least one attachment point, said' holding rail beingarranged on a plate means carried on said transverse carriage, saidplate means being urged by yieldable holding means against saidtransverse carriage at said at least one attachment point and beingyieldably responsive to displacements of said holding rail duringoperation of said press.

2. A holding rail arrangement in accordance with claim 1, in which saidplate means has a conical dished portion and said yieldable holdingmeans comprises a pin means fixed at its lower end in said transversecarriage, a first disc with a conical seat disposed around said pinmeans and fitting against said conical dished portion of said platemeans, a helical spring disposed around said pin means carried on saidfirst disc; a second disc disposed around said pin means and carried bysaid helical spring and at least one setting nut, which is screwed onthe upper end of said pin means against said second disc so that saidsecond disc presses against said helical spring and causes said springto constantly urge said first disc against said plate means.

3. A holding rail arrangement in accordance with claim 1, in which saidyieldable holding means is arranged on continuous rails which arefixedly disposed on said plate means, said rails having an obliqueseating surface in such a manner that relative longitudinal movementbetween said plate means and said transverse carriagc is possible.

4. A holding rail arrangement in accordance with claim 3, in which saidholding rail is attached to said transverse carriage at at least twoattachment points, one attachment point being arranged to act as a fixedpoint while the remaining points are so arranged that they allow fordifferential longitudinal expansion between said plate and saidtransverse carriage.

5. A holding rail arrangement in accordance with claim 2, in which ateach said attachment point of said holding rail electrical switches areprovided having plungers, each plunger being held in a non-operativeposition by a pressing screw mounted on said plate means so that ondisplacement of. said holding rail said pressing screw releases theplunger of each respective switch for stopping a drive means of saidcoordinate table.

1. A holding rail arrangement for a holding device on a coordinate tableof a punching press, which coordinate table has a transverse carriage,said arrangement comprising a holding rail movably fixed on saidtransverse carriage at at least one attachment point, said holding railbeing arranged on a plate means carried on said transverse carriage,said plate means being urged by yieldable holding means against saidtransverse carriage at said at least one attachment point and beingyieldably responsive to displacements of said holding rail duringoperation of said press.
 2. A holding rail arrangement in accordancewith claim 1, in which said plate means has a conical dished portion andsaid yieldable holding means comprises a pin means fixed at its lowerend in said transverse carriage, a first disc with a conical seatdisposed around said pin means and fitting against said conical dishedportion of said plate means, a helical spring disposed around said pinmeans carried on said first disc, a second disc disposed around said pinmeans and carried by said helical spring and at least one setting nut,which is screwed on the upper end of said pin means against said seconddisc so that said second disc presses against said helical spring andcauses said spring to constantly urge said first disc against said platemeans.
 3. A holding rail arrangement in accordance with claim 1, inwhich said yieldable holding means is arranged on continuous rails whichare fixedly disposed on said plate means, said rails having an obliqueseating surface in such a manner that relative longitudinal movementbetween said plate means and said transverse carriage is possible.
 4. Aholding rail arrangement in accordance with claim 3, in which saidholding rail is attached to said transverse carriage at at least twoattachment points, one attachment point being arranged to act as a fixedpoint while the remaining points are so arranged that they allow fordifferential longitudinal expansion between said plate and saidtransverse carriage.
 5. A holding rail arrangement in accordance withclaim 2, in which at each said attachment point of said holding railelectrical switches are provided having plungers, each plunger beingheld in a non-operative position by a pressing screw mounted on saidplate means so that on displacemenT of said holding rail said pressingscrew releases the plunger of each respective switch for stopping adrive means of said coordinate table.